Meralgia paresthetica is a lesion of the lateral cutaneous nerve of the thigh, most often occurring in the inguinal region and often associated with its age—related degenerative changes. It is manifested by paresthesia, pain and numbness of the lateral and partially anterior hip area, with intense pain syndrome — a violation of walking. The diagnosis of neuropathy is established mainly according to neurological research, additional examination of the patient is carried out using ultrasound, radiography, CT and includes examination of the spine, abdominal cavity, hip joint. Treatment involves pharmacotherapy, local administration of drugs, the use of physiotherapy methods, reflexology and massage. In difficult cases, surgical decompression of the nerve is possible.
General information
Meralgia paresthetica is observed mainly in men after the age of 50 (men 50-60 years old account for 75% of cases). It occurs in pregnant women, more often in the third trimester, which is associated with a change in their pelvic position.
In most clinical cases, meralgia paresthetica has a unilateral character. Bilateral lesions account for about 20%. There are family cases of neuropathy, probably due to genetically determined features of the structure of the nerve and its surrounding anatomical structures.
Anatomical features
The external, or lateral, cutaneous nerve of the femur originates from the anterior branches of the spinal roots L2-L3. Going from the front along the surface of the iliac muscle, it reaches the upper anterior iliac spine, medial to which it passes under the inguinal ligament and passes to the antero-lateral surface of the thigh, where it divides into 2-3 terminal branches. When exiting the thigh, the lateral cutaneous nerve forms a rather sharp bend posteriorly. In 17% of the observations, there was a fusiform thickening of the nerve trunk at the site of the bend.
A feature of the nerve is the occurrence of age-related degenerative changes in the pulp fibers, which explains the manifestation of paresthetic meralgia mainly in elderly people. The changes occurring in the nerve are described as a decrease in the diameter and number of pulp fibers with the secondary development of sclerotic processes. At the same time, there is no compensatory hypertrophy of the nerve membranes, only their densification is observed.
The lateral cutaneous nerve of the thigh and its branches extending to the knee joint innervate the outer and partially anterior surface of the thigh. The most vulnerable part of the nerve is the place of its exit to the thigh. The presence of a bend in the nerve trunk, its passage under the inguinal ligament and near the bone cause the rapid occurrence of nerve compression with any changes in this anatomical area.
Causes
Among the triggers that can cause Bernhardt-Roth disease, the most common are factors that cause nerve compression in the groin area. These include: wearing a corset, a tight belt or excessively tight underwear; obesity; pregnancy; curvature of the spine (scoliosis, lordosis); hip joint injuries and pelvic bone fractures; musculotonic and neuro-reflex changes occurring in diseases and injuries of the spine (lumbar radiculitis, osteochondrosis, discogenic myelopathy, fracture lumbar spine). The above reasons lead to changes in the relative position of the anatomical structures of the inguinal ligament, causing the friction of the nerve on the ligament or spine of the ilium when bending forward and hip movements.
Compression of the lateral cutaneous nerve is possible at the level of the iliac muscle. Its cause may be retroperitoneal hematoma, inflammatory processes of the abdominal cavity, pelvic varicose veins, tumors, surgical interventions. Like other mononeuropathies (for example, sciatic nerve neuropathy, femoral neuropathy, peroneal and tibial neuropathy), Bernhardt-Roth disease can occur with alcoholism, diabetes mellitus, heavy metal poisoning, systemic vasculitis, rheumatism, infectious diseases.
Symptoms
As a rule, meralgia paresthetica has a gradual onset. The disease manifests with numbness of some areas of the skin on the side of the thigh. Then the numbness spreads to the entire lateral and partially anterior surface of the thigh. Patients describe it as a feeling of “deadening of the skin” or “covering the thigh with tissue.” Paresthesia joins — local sensations of cold, burning, pressure, goose bumps, trembling, tingling. Initially, these symptoms are periodic in nature, provoked by the friction of clothing, walking or standing. In the future, they are constantly present. Along with paresthesia, a pain syndrome occurs, the intensity of which decreases when the patient lies with his legs bent. Pain makes walking difficult. The gait becomes like an intermittent limp.
Examination reveals hypesthesia corresponding to the innervation zone of the external cutaneous nerve. Tactile and pain sensitivity usually falls out, sometimes temperature sensitivity. In some clinical cases, hyperesthesia is observed, reaching hyperpathy. Trophic disorders may occur — hair loss, thinning of the skin, anhidrosis. Palpation of the exit point of the cutaneous nerve on the thigh provokes the occurrence of pain radiating along the thigh. The motor sphere is preserved. Limitations of motor function are completely due to pain syndrome.
Diagnostics
The criteria for verifying the diagnosis of “meralgia paresthetica” are the data of a neurological examination. Determining the genesis of neuralgia may require consultation with an orthopedist, lumbar spine x-ray, CT of the spine, hip joint x-ray, ultrasound or CT of the joint, ultrasound of the abdominal cavity and pelvis. Electromyography or electroneurography is required in extremely rare cases.
Differential diagnosis of Bernhardt-Roth disease is carried out with lumbar radiculopathy, coxarthrosis, lumbar spondyloarthrosis.
Treatment
Effective treatment of paresthetic meralgia is a combination of medication, physiotherapy and reflexotherapy methods. Performed by a neurologist. Of particular importance in this case is the elimination of triggers that caused the development of neuropathy. For example, weight loss, removal of tumors, treatment of hip joint pathology, correction of vertebral disorders.
Pain relief is carried out by prescribing anti—inflammatory drugs and analgesics (nemisulide, ketorolac, ibuprofen, etc.), in difficult cases – by local administration of local anesthetics (lidocaine, novocaine) or glucocorticoids (hydrocortisone, diprospan) in the form of blockades. Improvement of the trophism of the affected nerve is achieved by the use of vasoactive agents (nicotinic acid, pentoxifylline) and metabolic pharmaceuticals (thioctose, thiamine, cyanocobalamin, pyridoxine and their combinations).
Physiotherapy is prescribed after consultation with a physiotherapist. It can include darsonvalization, mud treatment, hydrogen sulfide or radon baths, massage. It is possible to perform acupuncture or electroacupuncture. However, the effectiveness of reflexotherapy largely depends on the professionalism of the reflexologist.
In some cases, in the absence of the proper effect of conservative treatment and the presence of intense pain syndrome, the question is raised about surgical intervention in the inguinal ligament, with the aim of decompression of the nerve.